Field
The relates to a device for machining a planar workpiece, having a machine stand which has a support surface (application surface) for a planar workpiece, and further having a machining head which can be moved relative to the support surface, which machining head has a tool for machining the workpiece and also has a holding unit (“hold-down unit”) with a pressure plate whereby the workpiece is pressed against the supporting surface by means of said pressure plate. Such a device is known from DE 10 2008 014358 A1.
Discussion
This section provides background information related to the present disclosure which is not necessarily prior art.
Devices of this general type are used in particular for fabrication of the interior structure of switching panels. The electronic components of the switching panels are disposed on the mounting plate according to a distribution pattern, which may be optimized, e.g., based on thermal considerations or based on the wiring configuration. With the aid of the inventive device, it is possible to provide openings, recesses, and the like in the mounting plate, in accordance with the distribution pattern, which openings, recesses, and the like serve for mounting of the electronic components or for heat removal from said components.
For machining of the mounting plate, a machining head which has a tool, e.g. a milling cutter, is guided over the workpiece. With flat workpieces, such as mounting plates, the machining may result in “bulging” of the workpiece, or development of vibrations, which will negatively affect the service life of the tool and the achievable speed of advance of the tool.
The vibrations which occur are frequently accompanied by substantial noise emissions.
In order to avoid the “bulging” and the vibrations, according to DE 10 2008 014358 A1 it is proposed to equip the machining head with a holding unit which has a pressure plate which serves to press the workpiece against the support surface. As a rule, the planar workpiece is attached to the machine stand by means of mounting claws or clamps which engage the peripheral region of the workpiece. The pressure plate known from the prior art has the drawback that it can collide with the mounting claws or clamps when the machining head is machining the workpiece in the peripheral region. With devices according to the prior art, it is impossible to machine the workpiece in the region near its edge region (peripheral region). Instead, current practice is to retract the pressure plate in the peripheral region of the workpiece, so that the mounting claws or clamps can be passed over without colliding with the pressure plate. However, this results in the workpiece swinging or “bulging” as a result of the machining process, with the adverse effects described above.